TOG: understanding baby sleeping bags and room temperature

What is TOG?

You keep seeing it on sleeping bag labels... and you're wondering, "What does that actually mean?"
Where's the instruction manual when you need it?

So, how does TOG work?

TOG is the thermal rating of a baby sleeping bag.

It stands for Thermal Overall Grade. Three words you probably weren't expecting to learn when you became a parent.

The higher the TOG rating, the warmer the sleeping bag.

It's a standardised measurement that's laboratory tested and used consistently across brands.

In other words, TOG tells you how well a baby sleeping bag retains heat.

But it's only part of the story.

What TOG doesn't tell you

TOG doesn't measure how warm your baby actually feels, because that depends on other important factors.

• The room temperature
• What your baby is wearing underneath

Together, these two factors are the best guide to choosing the right baby sleeping bag.

📊 TOG ratings explained

Baby sleeping bags range from 0.5 TOG for warm summer nights to 4.0 TOG for very cold weather.

In between, you'll find plenty of options to suit every season and every bedroom temperature.

That's the theory. But what does it actually mean for your baby sleeping peacefully in the next room?

Why is choosing the right TOG so important for your baby's comfort?

Babies don't regulate their body temperature the same way adults do. Their temperature regulation system is still developing until around the age of three. They can overheat more easily and also lose body heat faster than we do.

In other words, bedtime often becomes a bit of a balancing act. If there were Olympic medals for choosing the right sleepwear, parents would definitely deserve one.

Too warm: your baby may become restless, sweaty and wake more often.
Too cold: they may wake up because their body is using energy to stay warm instead of resting.

A baby sleeping bag won't magically solve sleep problems — that kind of magic belongs in fairy tales, not the nursery.

There isn't a miracle formula for sleeping through the night just yet. But choosing the right baby sleeping bag is one thing we can help make much simpler.

The right baby sleeping bag is simply the one that matches the actual room temperature, because the weather — and our homes — don't always behave as expected.

Always rely on a room thermometer in your baby's bedroom rather than the temperature elsewhere in the house. Even a difference of just a few degrees can make a real difference to your baby's comfort.

A bedroom temperature of 18°C to 20°C is generally recommended for babies.
From there, you can choose the right TOG rating and adjust the layers underneath accordingly.

Which TOG rating should you choose for your baby's room temperature?

Here's your quick reference guide. Just remember the temperature in your baby's room — we'll take care of the rest.

0.5 TOG: hot summer nights

Think of those heatwave evenings when the bedroom is still 27°C, even though the fan has been running all day. An ultra-lightweight baby sleeping bag is made for exactly this: keeping your baby covered without overheating. Cotton, muslin or bamboo fabrics help keep air flowing around delicate skin.

Above 26°C, a bodysuit on its own is usually enough. Open the windows once the outdoor temperature starts to cool down.

1.0 TOG: mild nights

Ideal for bedrooms between 22°C and 24°C. Lightweight enough to prevent overheating while still keeping your baby comfortably covered. Perfect for those late summer evenings when the nights start feeling just a little cooler.

1.5 TOG: the all-rounder

Best for room temperatures between 20°C and 22°C. Perfect for those in-between seasons when the weather can't quite decide what it's doing.

2.0 TOG: the everyday favourite

Between 18°C and 20°C, a 2.0 TOG baby sleeping bag is suitable for most nights of the year. Pair it with a long-sleeved bodysuit and a lightweight cotton sleepsuit and you're all set.

It's often the sleeping bag parents reach for without even thinking because it works in so many situations.

2.5 TOG: chilly nights

Designed for bedrooms between 16°C and 18°C. Ideal if your home is less insulated, the bedroom gets cold overnight or temperatures fluctuate during autumn and early spring.

3.0 TOG: winter has arrived

Recommended for room temperatures between 14°C and 16°C. It keeps your baby warm without adding unnecessary layers. If your baby's bedroom stays at a steady 20°C throughout the night, a 2.0 TOG sleeping bag is usually the better choice.

4.0 TOG: for the coldest nights

Suitable for bedrooms below 14°C. If the heating comes back on during the night, simply check the back of your baby's neck and adjust clothing if needed. One quick check is usually all it takes.

How can you tell if your baby is comfortable in their sleeping bag?

Your baby's hands and feet will almost always feel cool. That's simply part of how they regulate their body temperature — it's not usually a cause for concern.

The best place to check is the back of their neck or their upper back. Gently place your hand between your baby's shoulder blades for around ten seconds.

• Warm and clammy neck → remove one layer.
• Warm and dry neck → perfect, no need to change anything.
• Cool neck → add one layer.

One hand on the back of the neck, ten seconds, and you've got your answer. No batteries. No app. 😄

Multi-TOG baby sleeping bags: the all-in-one solution?

Removable sleeves, detachable layers and a TOG rating that changes depending on how it's assembled. It sounds perfect on paper. In reality? It depends.

If you travel often or like to pack light, a multi-TOG baby sleeping bag can be a real lifesaver. One sleeping bag can replace two, saving valuable space in your suitcase.

If your baby wriggles through every nappy change and the thought of adding or removing layers at 11 pm already feels exhausting, two well-chosen sleeping bags with fixed TOG ratings might be the more practical option.

The best baby sleeping bag is the one you actually use. Sometimes, the simplest solution is also the one that works best.

What size baby sleeping bag should you choose?

Sleeping bag sizes are based on length. Your baby should be able to move their legs freely, but their feet shouldn't touch the bottom. Otherwise, they may slide down inside the sleeping bag, causing it to ride up.

• 0–6 months: 60–70 cm
• 6–18 months: 70–90 cm
• 18 months–3 years: 90–110 cm

If your baby is between two sizes, choosing the larger one often means they'll be able to use it for longer. As long as the shoulders fit securely, they'll stay comfortable.

It's also worth looking for the OEKO-TEX® STANDARD 100 label, which certifies that the fabrics have been tested for harmful substances and are suitable for your baby's delicate skin.

When it's time to wash your baby's sleeping bag, skip the fabric conditioner — it's the one thing to avoid. Wash at 30°C and leave it to air dry.

If you're choosing a baby sleeping bag based on your child's age or the season, comparing different styles and TOG ratings can help you find the right option.